title: In vivo human time-exposure study of orally dosed commercial silver nanoparticles.
abstract: Human biodistribution, bioprocessing and possible toxicity of nanoscale silver receive increasing health assessment. We prospectively studied commercial 10- and 32-ppm nanoscale silver particle solutions in a single-blind, controlled, cross-over, intent-to-treat, design. Healthy subjects (n=60) underwent metabolic, blood counts, urinalysis, sputum induction, and chest and abdomen magnetic resonance imaging. Silver serum and urine content were determined. No clinically important changes in metabolic, hematologic, or urinalysis measures were identified. No morphological changes were detected in the lungs, heart or abdominal organs. No significant changes were noted in pulmonary reactive oxygen species or pro-inflammatory cytokine generation. In vivo oral exposure to these commercial nanoscale silver particle solutions does not prompt clinically important changes in human metabolic, hematologic, urine, physical findings or imaging morphology. Further study of increasing time exposure and dosing of silver nanoparticulate silver, and observation of additional organ systems are warranted to assert human toxicity thresholds.
  
  
  BACKGROUND
  In this study, the effects of commercially available nanoparticles were studied in healthy volunteers, concluding no detectable toxicity with the utilized comprehensive assays and tests. As the authors rightfully state, further studies are definitely warranted. Studies like this are much needed for the more widespread application of nanomedicine.
authors.affiliation: Department of Pharmacotherapy, University of Utah, Salt Lake City, UT, USA; Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA. Electronic address: mmunger@hsc.utah.edu.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Munger
authors.affiliation: Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, USA.
authors.forename: Przemyslaw
authors.initials: P
authors.lastname: Radwanski
authors.affiliation: Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, USA.
authors.forename: Greg C
authors.initials: GC
authors.lastname: Hadlock
authors.affiliation: Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.
authors.forename: Greg
authors.initials: G
authors.lastname: Stoddard
authors.affiliation: Department of Radiology, University of Utah, Salt Lake City, UT, USA.
authors.forename: Akram
authors.initials: A
authors.lastname: Shaaban
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Falconer
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Grainger
authors.affiliation: Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, USA.
authors.forename: Cassandra E
authors.initials: CE
authors.lastname: Deering-Rice
mesh_terms: D000328:Adult; D000368:Aged; D001772:Blood Cell Count; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging / Q000187:drug effects*; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D053768:Metal Nanoparticles / Q000008:administration & dosage* / Q000009:adverse effects; D008875:Middle Aged; D013902:Radiography, Thoracic; D017382:Reactive Oxygen Species / Q000378:metabolism; D012834:Silver / Q000008:administration & dosage* / Q000009:adverse effects; D013183:Sputum / Q000378:metabolism; D016482:Urinalysis
chemical_list: D017382:Reactive Oxygen Species; D012834:Silver
keywords: Biological activity nanoparticles; Nanotechnology; Nanotoxicology oral ingestion; Safety research